Enterprises can now run custom actions during feature update: In RS4, we are adding a new feature that will enable your enterprise to run your own custom actions/scripts synchronously with setup. Setup will execute custom actions during two update phases controlled by using preinstall.cmd or precommit.cmd:

Pre-install: This would be just before all the system and device compatibility scans run.

Pre-commit: This would be just before the system reboots into the offline phase.

Setup also migrates the scripts for future updates. In the event of an update failure or rollback, a failure.cmd script can be used to perform custom operations or undo actions of previous custom scripts.
Run (Migrate):

C:\Windows\System32\update\run\<GUID>\preinstall.cmd

C:\Windows\System32\update\run\<GUID>\precommit.cmd

C:\Windows\System32\update\run\<GUID>\failure.cmd

C:\Windows\System32\update\run\<GUID>\reflectdrivers\foo.inf

C:\Windows\System32\update\run\<GUID>\reflectdrivers\foo.sys

Run Once (Do not migrate):

C:\Windows\System32\update\runonce\<GUID>\preinstall.cmd

C:\Windows\System32\update\runonce\<GUID>\precommit.cmd

C:\Windows\System32\update\runonce\<GUID>\failure.cmd

C:\Windows\System32\update\runonce\<GUID>\reflectdrivers\bar.inf

C:\Windows\System32\update\runonce\<GUID>\reflectdrivers\bar.sys

Enterprises can run post rollback scripts in system context​: Current /postrollback scripts run if the first user logs in after the rollback has admin privileges. We received feedback from several enterprises that most of their employees don’t have admin privileges. With RS4, we are enabling /postrollback scripts to run in admin context or system context.

We are not changing the behavior of the existing /postrollback switch. We have added a new switch /postrollbackcontext “xxx” to be used along with /postrollback switch to specify in which context should the scripts be executed:

Docker for Windows users, we are flighting the matching Windows container images of Server Core and Nano Server to the Docker Hub for continued testing and feedback. Thank you for all the great feedback and please keep it coming!

General changes, improvements, and fixes for PC

We fixed an issue where buttons on Game bar were not centered correctly.

We fixed an issue where a small number of PCs might have experienced one CPU under persistent high load or even a bugcheck (GSOD with error DPC_WATCHDOG_VIOLATION).

We fixed an issue where tearing a PDF tab in Microsoft Edge would result in a bugcheck (GSOD).

We fixed an issue resulting in some app icons appearing distorted in Task View.

We fixed an issue where making a pinch gesture over the open apps in Task View might result in no longer being able to scroll down to Timeline.

We fixed an issue where pressing and holding on a card in Timeline would open the corresponding app, rather than bringing up a context menu.

We fixed an issue resulting in the title bar overlapping content when you opened your lists in Cortana’s notebook.

We’ve updated the new notification to fix blurry apps so that it now will persist in the Action Center to be accessed later once the toast has timed out and dismissed.

We fixed an issue where it wasn’t possible to open a new inPrivate window of Microsoft Edge from the taskbar jumplist while in Tablet Mode.

We fixed an issue where dragging a Microsoft Edge tab out of the window and releasing hold of it somewhere over the desktop might periodically result in a stuck invisible window.

We fixed an issue resulting in DirectAccess not working in recent builds, where the connection would be stuck with status “Connecting”.

We fixed an issue where the touch keyboard number pad would show the period as a decimal separator for countries that use the comma as a decimal separator.

We fixed an issue resulting in not being able to turn on and off third party IMEs using the touch keyboard.

We fixed an issue resulting in numbers not being inserted when flicking up on the top row of letters in the wide touch keyboard layout.

Known issues

IMPORTANT: The Microsoft Store may be completely broken or disappeared altogether after upgrading to this build. Please see this forum post for details including a workaround on how to get the Microsoft Store back.

Selecting a notification after taking a screenshot or game clip opens the Xbox app’s home screen instead of opening the screenshot or game clip.

Post-install at the first user-prompted reboot or shutdown, a small number of devices have experienced a scenario wherein the OS fails to load properly and may enter a reboot loop state. For affected PCs, turning off fast boot may bypass the issue. If not, it is necessary to create a bootable ISO on a USB drive, boot into recovery mode, and this this will allow bypass.

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